I cannot access my phone after system upgrade, why?

Hi, welcome to the forums! Could you give us more details about your problem? What happens when you try to power the phone on? Is it in a bootloop, does it get unresponsive after some time, do you get any kind of error?

After you plug the phone into your PC and pull down the notification bar do you see a notification saying "Connected as a media device"? If so click that and select MTP and then you should be able to access your file using your PC.

It depends. If there's debris in the port, use a can of compressed air to blow it out. But if the pin itself is damaged, you'd probably have to get it replaced (by either a repair shop, or by Samsung if the phone is still under warranty).